358 BULLETIN OF THE BUREAU OF FISHERIES. 



ment, with strongly convex sides. Abdomen three- jointed, the joints all about the same width and 

 length; anal laminse nearly as long as the entire abdomen, narrow and enlarged at the tip into a rounded 

 knob on the outer margin, each tipped with two long plumose setae, the inner of which is one-half 

 longer than the outer. Egg strings elongate ellipsoids, a little shorter than the cephalothorax; eggs 

 large, arranged in 6 or 7 longitudinal rows, about 8 eggs in the longest rows. 



First antennae exceptionally large, six-jointed, the jointing indistinct, the fourth segment carrying 

 on the inner distal comer a huge jointed seta, which reaches back to the center of the second thorax 

 segment; the terminal joint is tipped with another huge seta, unjointed but nearly as long as the jointed 

 one. Second antennae also long but slender, the terminal claw bltintly roimded. Mouth tube pro- 

 truding strongly; mandibles with a short neck and cutting blade, turned forward diagonally; palp long 

 and narrow and armed along its inner margin with short bristles. 



First maxillae of the usual pattern; second maxillje meeting on the midline, the cutting blade short 

 and small and armed with a few sharp spines. Endopods of the first and foiuth legs longer than the 

 exopods; rami of the other legs equal; arrangement of the spines and setae as follows: First exopod, 

 l-o, i-i, 1-6; endopod, o-i, o-i, 0-6; second exopod, i-o, l-i, 1-5; endopod, o-i, 0-2, 1-4; third exopod, 

 l-o, i-i, 1-5; endopod, o-i, 0-2, 1-4; fourth exopod, i-o, 1-4; endopod, o-i, 0-2, 1-3. 



Color, a transparent yellowish white, oviducts white, egg tubes yellow, the ventral surface of the 

 carapace and thorax covered with irregular patches of a light sky-blue pigment. 



Total length, i ram.; carapace, 0.50 mm. long, 0.40 mm. wide; first antennae, including setae, 0.60 

 mm. long. Egg strings, 0.40 mm. long. 



(megaceros, likyai, large, and nipa^, horn, alluding to the large first and second antennae.) 



Remarks. — So far as known, this is the first parasitic copepod to be found in the nasal fossae of any 

 fresh-water fish. They are common in both the nasal fossae and spiracles of salt-water fish, sharks, and 

 rays, and probably the reason why they have never been found in fresh-water fish is simply because 

 they have never been looked for. The nostrils of this catfish were only quarter of an inch in diameter, 

 and hence the ergasilid larva must do some strenuous hunting to find its chosen place on the host. It 

 is more than likely that the examination of similar fossae on other large fresh-water fish will yield speci- 

 mens of this or similar species. Being found thus in the nose, the species can not be associated in any 

 way with mussel glochidia, but its presence emphasizes the testimony of those species found on the 

 gills, that the Fulton cat would make a good host for glochidia. If the ergasilid larva can find its way 

 into the nose of these fish, it is possible that the mussel glochidium can perform the same feat. At all 

 events it will be worth while to examine the nose of large fishes for both copepods and glochidia. 



£rgasilus elongatus, new species. (PI. lxvi, fig. 47, 48; pi. Lxvin, fig. 62-66.) 



Host and record of specimens.— Twenty-^ve females with egg strings were obtained from the gill 

 »<ikers of the spoonbill cat, Polyodon spathula, from the Mississippi River at New Boston, 111., July, 

 igi4, catalogue no. 47764, U. S. National Museum. Thirty females from the same host at Keokuk, Iowa, 

 August 28, 1914, catalogue no. 47763, U. S. National Museum. A single female (catalogue no. 47765, 

 U. S. National Museum) has been selected from this last lot to serve as the type of the new species. 

 Sections of two gills of the same fish, with specimens of the species in situ, have received catalogue no. 

 47762, U. S. National Museum. 



Specific characters of female. — General body form an elongate ovoid, the larger end anterior; cephalo- 

 thorax one-half longer than the rest of the body, widest at its center, strongly tapered anteriorly, almost 

 squarely truncated posteriorly. Antennal area reaching the entire width of the anterior end and dis- 

 tinctly separated from the rest of the head. 



Free thorax segments diminishing regularly in width and length from in front backwards; fifth 

 segment plainly visible and half the width of the foiulh; genital segment barrel shaped, its sides mod- 

 erately projecting. Abdomen segments the same length but diminishing regularly in width; anal 

 laminae half as long again as the last abdomen segment, narrow with square comers, each tipped with 

 two short setae, the inner of which is one-half longer than the outer. Egg strings to the entire length of 

 the body as 8 to 11, rather narrow ; eggs arranged in 6 or 7 longitudinal rows, about 25 in the longest rows. 



First antennae rather slender and short, six-jointed, and sparsely armed with setae; second antennae 

 also short but stout, not long enough to reach more than halfway aroimd the gill raker, but clasping it 

 so tightly as to make a groove in it. Mouth tube exceptionally far forward and not projecting as strongly 

 as in most species; upper lip rather square, and entirely covering the mouth parts. Mandibles as large 



